chore: fix travis + doc

Author: l-lin

.travis.yml

@@ -2,7 +2,7 @@ dist: trusty
 sudo: required
 language: node_js
 node_js:
-  - "8.11.1"
+  - "10.15.1"
 os:
   - linux
 env:

DEVELOPER.md

@@ -56,6 +56,12 @@ ncu -u
 rm -rf node_modules && npm install
 ```
 
+If you want to update angular, use the cli:
+
+```bash
+ng update @angular/cli @angular/core
+```
+
 ## Testing
 
 These tools are configured for specific conventions described below.

demo/src/app/getting-started.component.ts

@@ -5,7 +5,7 @@ import { Component } from '@angular/core';
   templateUrl: 'getting-started.component.html'
 })
 export class GettingStartedComponent {
-  nodeVersion = '8.9';
+  nodeVersion = '10';
   npmVersion = '6';
   angularCliVersion = '8.Y.Z';
   npmInstallSnippet = `

demo/src/app/welcome.component.ts

@@ -7,5 +7,5 @@ import { Component } from '@angular/core';
 })
 export class WelcomeComponent {
   angularjsDataTablesVersion = 'v0.Y.Z';
-  angularDataTablesVersion = 'v7.Y.Z';
+  angularDataTablesVersion = 'v8.Y.Z';
 }